Sunday, October 30, 2016

End of October Monster NE US Storms

25 years ago today coastal communities were dealing a powerful unnamed nor'easter that was nearing peak intensity as it moved towards New England.  High winds, cycles of major coastal flooding and heavy rains pounded the Northeast coast.  5 years ago today millions woke up in the dark after a stunning major snowstorm rocked the region.  4 years ago today millions more woke up with no power, many downed trees/power lines and coastal flooding not scene in decades along coastal areas from Hurricane Sandy.  Let's review these storms and then ask the question why late October seems to be a favorable time for generational weather systems.

The Perfect Storm October 28-November 2, 1991
On October 27, 1991 a cold front exited the east largely without incident.  At the same time Hurricane Grace was a Category 2 storm in the SW Atlantic near Bermuda.  A non tropical low formed on the cold front near Nova Scotia that began to move back towards New England.  Thanks to a set of rare atmospheric conditions that NWS Boston meteorologist Bob Case said take place only once every 50-100 years an explosive storm developed.
NOAA GOES 7 Infrared Satellite October 30, 1991
Strong high pressure across eastern North America contributed to the formation of this storm.  It stretched from the Gulf Coast to Greenland.    The strong pressure gradient between this (1043 mb in Canada) and the deepening extra tropical surface low brought hurricane force winds to the Northeast.  More damaging was the swells and storm surge caused by the giant storm.  Here is how the upper atmosphere evolved from October 28 8 PM to October 30 8 PM.  The big image to focus on is the blue and red 500 mb upper air chart on the right.
10-28-1991 Upper air 8 PM via NOAA/NWS/NCEP reanalysis 
The configuration here shows ample cold Canadian air pouring into the Northeast thanks to the ridge.  The Atlantic trough and Hurricane Grace are feeding off the warmer Atlantic waters.  Moving forward 24 hours
10-29-1991 Upper air 8 PM via NOAA/NWS/NCEP reanalysis
The ridge in SE Canada is strengthening while the nor'easter has absorbed Grace and continues to deepen as well.   By October 30 a major storm is crushing the east coast with wind and waves.
10-30-1991 Upper air 8 PM via NOAA/NWS/NCEP reanalysis
The Perfect Storm would stall over the Gulf Stream and it took on tropical characteristics.  The storm became a category 1 Hurricane but it was left with no name.  Damage in coastal New England rivaled some of the great storms in the regions history including the 1944 Great Atlantic Hurricane, 1962 Ash Wednesday Nor'easter, the Blizzard of 1978 among others (NOAA).  Inland it wasn't as bad as it could have been as the strongest winds were closer to the coast.
Storm Damage Rebecca Rd Scituate, MA
In summary cold Canadian air, warm tropical air and a hurricane created a monster in late October 1991.   See here for Channel 5's image gallery of the event.

Snowtober- The Halloween Nor'easter October 28-28, 2011
2011 is a historic weather year in Southern New England.  It started in winter with 4 NESIS rated snowstorms.  On June 1 we had the EF-3 Springfield tornado, in late August Hurricane Irene slammed into the region and in late October we had Snowtober.  The heaviest snow missed SE MA/RI but around 8" fell in Southern Worcester County.  Upwards of 1-2 feet fell in Western MA, CT, NY, and NJ.
NESIS Halloween Nor'Easter snow totals/ratings 
This was the second major weather event I covered as a professional.  I first posted on October 27 about the incoming threat. I broke it down even further on October 28 before one final update on October 29, the day of the storm.  One thing I missed with that forecast was the developing nor'easter pulling the remnants of Hurricane Rina into the storm.  That added extra moisture and energy into the storm.  Here is the surface map for Friday October 28 at 8 PM.
WPC Surface Analysis Friday October 28, 2011 8 PM
Four features to point out.  First high pressure over the Northeast.  This has locked in cold Canadian air.  Second is low pressure in Georgia.  This is the main surface low that will develop into the storm.  Third see the low along the US/Canadian border in Minnesota?  That will add energy to the storm and phase (combine energy) the northern and southern jet streams.  Finally in the Southern Gulf of Mexico between Mexico and Cuba is the remnants of Hurricane Rina.  Moving forward to Saturday 8 AM here is the upper atmosphere
10-29-2011 Upper air 8 AM via NOAA/NWS/NCEP reanalysis 
The big dip in the Great Lakes is the northern jet moving towards the east coast where a favorable environment for strong storm formation exists.  By 8 PM a closed surface low has formed and a classic mid winter nor'easter was on our hands in late October.
WPC Surface Analysis Saturday October 29, 2011 8 PM

This was by far the most significant winter storm of the 2011-12 season.  In fact this storm helped change the jet stream.  For the next year the atmosphere was mostly zonal meaning mild Pacific air flooded the US.  Still the damage from 2011 was done.
Telegraph UK photo of Belmont, MA October 30, 2011 snow damage
Post Storm visible satellite image showing where snow fell
In summary the northern and southern jet streams phased off the east coast while ingesting the remnants of a tropical cyclone.  At the same time Canadian high pressure locked cold air in place.  The result was a historic late October storm.  As for the next storm it hit a few hundred miles south of the region which spared most of New England from a devastating blow.

Hurricane Sandy October 28-29, 2012
Hurricane Sandy is second to only Hurricane Katrina when it comes to insured loses from a tropical cyclone.  Sandy brought strong winds, heavy rain, heavy snow, and a devastating storm surge to the most populated region in the States.   The center hit Southern NJ but severe coastal impacts occurred as far away as Newport, RI.  Inland high winds brought down trees and power lines.

Tuesday October 23, 2012 first thoughts
Thursday October 25, 2012 Sandy gains strength
Saturday October 27, 2012 Timing/Impacts
Monday October 29, 2012 The Day Of
The aftermath part 1

Sandy was a fascinating meteorological event. Over 100 people lost their lives in the US.
WPC Surface Analysis Monday October 29, 2012 2 PM
A cold front captured Sandy and turned the storm into a hybrid hurricane/nor'easter.  That is a common theme for these late October storms.  Some sort of tropical cyclone is either ingested or is acquired by an early season winter trough.  It is rare but sometimes a winter like trough is able to descend into Eastern North America.  The SW Atlantic/Caribbean Sea/Gulf of Mexico are all capable of supporting a hurricane in late October.  This tropical energy combining with non-tropical lows produces exceptionally strong storms in the Northwest Atlantic Ocean.  
Hurricane Sandy Damage in New Jersey
Hurricane Sandy damage in Rhode Island (via MassLive)
Thankfully it is quiet this Halloween.

-Zack Green



Some Rain But No Major Storms to End October

Some of the most infamous New England/Northeast weather events have occurred at the end of October.  Just in the last 25 years we have seen the Perfect Storm (1991), the Halloween Snowstorm (2011), and Hurricane Sandy (2012).  Nothing like that is in the forecast this year but a small system is moving through the Great Lakes that will bring rain to the northeast today.  Buffalo is seeing some of this rain right now and the first half of the Pats/Bills game looks wet.  A warming trend will take place into next week.

General Overview
Here is the current radar image for the northeast.  A batch of showers is accompanying an area of low pressure moving through the Great Lakes.  The rain is helping clean the streets of Cleveland before a potentially wild party tonight (if the Indians clinch).
NWS Northeast Regional Radar Loop 
Some of the storms near the PA/NY border have lightning accompanying the heavy rain.  The low will ride right across Southern New England along this cold front.
WPC Surface Analysis 8 AM Sunday
The rain will arrive around 5 PM in SNE.  First here is 1 PM.  Notice the heavy rain in Buffalo.  If I were a wagering man I'd think about the 1st qtr/half under in the Pats/Bills game.  The only other NFL game that will be impacted by precipitation is the Jets/Browns game in Cleveland.
12z HRRR Simulated Radar 1 PM
Here is the 6 PM radar image for the Northeast.
12z HRRR Simulated radar 6 PM (image Weatherbell)
By midnight the precipitation is offshore.
12z HRRR Simulated Radar 12 AM Monday (Image Weatherbell)
It looks like the Mass Pike is the dividing line between showers and heavier rain.  SE MA is looking at around an inch.  Southern Worcester County to Boston and south from Providence to Foxboro should see around 0.5".  If the low shifts a little north or south the heavy rain belt will move with it.
12z HRRR total precipitation through 2 AM (image Weatherbell)

Now precipitation is not the only weather factor that came impact a game.  That same cold front the rain is moving across is also a big temperature divider for the US.  You can see this in the forecast max temperature for the Northeast today.
NWS Northeast Regional Max Temps Sunday (image Weatherbell)
Temperatures in the Southeast will approach record level this afternoon.  The Raiders-Bucs and Falcons-Cardinals games will see max temps in the mid 80's.  The other games in the South today are indoors.  The white circles mean the NWS is forecasting record highs for those locations.
NWS Max temperature forecast/record potential Sunday (image Weatherbell)
Behind the rain a cold wind and cooler temperatures will flow into the region.  So the Halloween forecast is a chilly one.  First up tomorrow morning the back to work/school forecast is clear skies with a chilly north wind.  Morning lows in the 30's will give way to max temps in the upper 40's/near 50.   Tomorrow evening temps will be dropping back into the low to mid 30's.  So for the prime trick or treat hours expect clear skies with temps near 40.

Finally despite all this rain the drought will take many months to fully recover from.  The recent rains may have added some water to reservoirs and some folks with dug wells may have added rain to their stock.  But for the agriculture and long term water storage situation we have a long way to go.
US Drought Monitor Red-Extreme Orange-Severe Light Orange- Moderate Yellow-Abnormally Dry
Coming later today- the End of October Major Storms

-Zack Green

Wednesday, October 26, 2016

Update on Thursday Precipitation

Overnight lows in the upper 20's will give way to rain and snow in the New England.  Most of the snow is in the higher elevations of Western and Northern New England but even Central Mass should see a few flakes before switching over to all rain.  No accumulation is expected but if you are in the Leominster-Springfield-Hartford regions the roads may be slick.  "Warmer" air will make this a rain storm for Southern New England Thursday PM into Friday AM when 0.5-1.5" (locally higher) will fall.

General Overview
High pressure in Ontario will keep this cold air mass in place tonight.  Low will drop into the mid 20's.  Urban areas, the immediate coast, and anywhere that gets wind off the ocean.  The Atlantic is still in the upper 50's so that will keep temperatures in the mid 30's.
NWS Minimum Temperature forecast Wednesday-Thursday (Image Weatherbell)
High temperatures today maxed in the 40's.  That is 10-13 degrees below average for this time of year.  However both systems move east overnight.  First here is what the lower level of the atmosphere will look like at 2 AM tonight.
WPC Surface Forecast Thursday 8 AM
As the low moves east snow will begin to fly in Eastern NY and Western New England.  However the high will hold strong early tomorrow.  Precipitation will likely hold off through 8 AM.  Here is the simulated radar for that time.
21z HRRR simulated radar Thursday 8 AM (image Weatherbell)
That means most of the AM commute is fine.  Temperatures will rise into the 40's by 11 AM so any snow flakes will have to mix in before then.
21z HRRR 2 m temperatures Thursday 11 AM (Image Weatherbell)
By Thursday evening it will be raining steadily in Southern New England.  The original low will give way to a new surface low along the New England coast Thursday night into Friday.  As that happens a band of heavy rain will set up across the region.  Notice the low near Buffalo at this hour.
18z NAM Hires Simulated Radar Thursday 8 PM (image Tropical Tidbits)
By 8 AM it has reformed near Cape Cod and most of the precipitation is pulling away into Northern New England.
18z NAM hires simulated radar 8 AM Friday (image Tropical Tidbits)
Temperatures will be in the 50's Friday AM.  Overall I expect 0.75-1.5" of rain but a few localized spots will see more.  October has been a wonderful month for the drought although I do need to correct an item from my Saturday AM blog Wicked Rain Overwhelms SNE.  At the time of writing I was unaware that Jacob Goulet of Nashua, NH fell into a storm drain and was swept away.  My apologies and condolences to those who knew/loved Jacob.

-Zack Green

Tuesday, October 25, 2016

Cold Air Mass Settles Over Region

Its a chilly start across the Northeast this AM and it won't improve much as the day wears on.  Temps are firmly in the mid 30's.  A brisk west to northwest wind will make temperatures in the 40's feel closer to the upper 30's.  Its even colder tomorrow and Thursday AM when snow (yes snow) is possible before a change over to rain.

General Overview
Here are the low temperatures as of 5 AM.  Its near 40 in the eastern urban areas (Boston) and also where the ocean is moderating the air temperature.
4 AM 2 m temps (image Weatherbell)
Counter clockwise flow around low pressure in E Canada and clockwise flow around high pressure in Ontario are forcing a true Canadian air mass south.
WPC Surface Analysis 2 AM 
This combo will help keep temperatures in the upper 40's today and will produce winds gusting to near 30.  It will be mostly sunny but the cold and wind will win out to produce a chilly afternoon.  SE MA is the warmest today with max temps near 50.
NWS Max temp forecast Tuesday (image Weatherbell)
Tonight there is a freeze threat for areas in Eastern MA that have not yet ended the growing season.  We have already had a freeze in Worcester County so we are not included in the freeze warning.  We will still drop below freezing tonight.
NWS Headlines Tuesday October 25, 2016
Some showers are possible tonight on the Outer Cape so temperatures will not fall as hard.  Expecting near 30 in Worcester County and mid to upper 20's in the coldest areas (Norwood, Orange etc.).
NWS min temps overnight Tuesday into Wednesday (image Weatherbell)
High pressure becomes the dominant feature during the day Wednesday.  As a result the winds will lessen but the high will introduce the coldest air of the season to our skin.  High temperatures tomorrow will again be in the mid to upper 40's,  A storm system in the Great Lakes will begin to take shape on Wednesday PM.  It may bring some showers to Game 2 of the World Series.  Here is the surface forecast for Wednesday 8 PM.
WPC Surface Forecast Wednesday 8 PM
Temperatures will plummet Wednesday night into the upper 20's for even Southern New England.  We are in the low 20's in Central New England!
NWS min temps Wednesday night to Thursday morning (image Weatherbell) 
 The Great Lakes system will move east and run into this cold air.  The cold will win for the first few hours of the storm which should produce some wintry precipitation all the way to 95.  Accumulation is doubtful on the roads but grassy areas may be covered before a changeover to rain.  It will be slick for the commute.
WPC Surface Forecast Thursday 8 AM
The changeover will occur between 8-10 AM as temperatures return to the 40's.  Thursday afternoon is just a raw mid fall day.  Steady rain some wind and cold temperatures.  We aren't here yet but its coming...and don't be this person.
Bad Winter Driving
-Zack Green

Saturday, October 22, 2016

Wicked Rains Overwhelm SNE

Over 3" of rain fell in less than hour last night as a cold front and subtropical low pressure system combined to produced drought denting rains.  The drought helped contribute to the flash floods as the rain came down so fast none was absorbed by the dry ground.  Water rain right into streets and overwhelmed storm drains that were covered in leaves.   Another round of rain will move through between 11 AM- 4 PM.  Then winds will pick up with gusts approaching 45-50 MPH tonight before lessening slightly Sunday.

The Aftermath
You can check out all the flooding reports here.  All of the rainfall reports can be found here but I wanted to highlight a few.  I expected a few 3" rain amounts but what happened in Worcester County is ridiculous.
Rainfall in inches 
Some isolated showers moved through the region yesterday morning and early afternoon.  Around 4 PM the heavy torrential rain bands began to rotate into Central MA with rainfall coming down at over an inch per hour.  The first whack lasted for about 20-25 minutes.  The main event began around 6 PM with driving tropical rains and thunder and lightning.  This is a video via 7 News of Worcester.
The Worcester Telegram & Gazette has a nice collection of stories and videos.  Many people were stranded on 290 or under bridges as the rain rate was just too fast for the drainage to keep up.  This tweet sent by Worcester Buzz captures the astonishment of residents on Elm Street as waters rise to the front porch.  I feel for everyone who had to deal with feet of water in the basement or cars that were ruined.
Tweet by Worcester Buzz via T&G
For my visual followers here is the precipitation analysis plotted for the last 24 hours.
NWS precipitation analysis 10/21/2016 (image Weatherbell)
When we see flooding pictures from North Carolina, West Virginia, or Louisiana its hard to image the amount of rain and water that actually fell.  Image rain like we had last night for a day (or more).  High winds and big snowstorms are sexy but its the water that always causes the most death and destruction.  Thankfully I haven't see any reports of causalities from the flooding.  The awful situation in Boston was not caused by these rains.

Short Term Forecast
We have another round of rain ready to rotate across our region.  The main rain band is already to Hartford but some showers have fired out ahead of this.
NWS Northeast Regional Radar 
 Here is the surface chart for the Northeast.  The low is going to back into Maine pulling the moisture east and then north.  So we won't get most of that precipitation in Upstate New York.  But the tail around NJ will rotate across Southern New England.  Rain within this band will be heavy at times.  I don't see a lightning signature as of now which is good news but that could change.  The atmosphere is unstable (though not as bad as last night).
WPC Northeast Surface Analysis 8 AM
The latest futurecast does show a fairly strong thunderstorm between 1-2 PM before a brief dry slot works into RI/CMass between 3-5 PM.  Showers will resume this evening.
14z HRRR Simulated Radar 2 PM (image Weatherbell)
Here is the 4 PM simulated radar.  This is concerning for the North Shore/NE MA/NH/S ME.  This band looks like what hit Central MA last night.
14z HRRR Simulated Radar 4 PM (image Weatherbell)
If you happen to live in this region or have to travel this way please check the radar.  Flooded roads are no joke.  Oh and yes that is snow in New York.  I doubt any makes it to SNE unless is in the Worcester Hills as flurries overnight.  Of bigger concern is the winds after this system clears.  The National Weather Service has posted a *Wind Advisory*  from 8 PM tonight to 2 PM Sunday.
NWS Boston Headlines
As the storm pulls away it will gain strength in the Canadian Maritimes.  High pressure will settle into the region bringing a Canadian air mass with mid week temperatures barely making 50 (more on that tomorrow).  In the meantime the large difference in atmospheric pressure to our north and south will force strong winds to squeeze between the two right over New England.  As a result frequent gusts of over 35-45 MPH are likely tonight with a few 50+ gusts likely.

Temperatures this afternoon will also crash.  Can you tell me where the cold front is?
14z HRRR 2 m temps 11 AM (image Weatherbell)  
By 5 PM the 40's come calling
14z HRRR 2 m max temp 5 PM (image Weatherbell)
We drop into the 30's tonight.  I'll discuss next week's weather tomorrow.

-Zack Green

Friday, October 21, 2016

Rain Will Pick Up In Intensity This PM

It's a dreary morning with fog and a few showers.  Temperatures are in the mid to upper 50's.  Temps will max in the low 70's.  Saturday will be windy and much cooler.  Although high temps will be in the low 60's tomorrow this will occur in the morning before crashing in the afternoon as the west wind picks up and gusts to near 30 MPH.

General Overview
Here is the northeast regional radar loop as of 630 AM.
NWS Northeast Regional Radar Loop
The actual cold front responsible for all that heavy rain in the Ohio Valley and up into PA and NY is a slow moving frontal boundary.  Its unlikely we see much rain from the actual front as low pressure tracks into Northern New England.  Still the involvement of subtropical moisture will produce locally heavy rain this afternoon as precipitation will be enhanced by the offshore passage of that storm.   Simulated radar at 2 PM shows some rain bands beginning to work across SNE.
09z HRRR Simulated radar 2 PM (image Weatherbell)
Given the atmospheric situation we could see some thunderstorms this afternoon.  I would peg the threat between 2-10 PM.  Here is the 6 PM radar
09z HRRR Simulated Radar 6 PM (image Weatherbell)
This model shows Eastern MA and RI getting crushed with rain this evening.  Moving forward to 10 PM
09z HRRR Simulated Radar 10 PM (image Weatherbell)
High school football games in CMass, EMass and RI will be wet (and possibly delayed by lightning).  The storm will produce a dry slot but not until after midnight.  Drizzle and fog will remain through Saturday AM.   Total rainfall is 1-2" (locally higher).  Temperatures will be in the 60's when we wake up tomorrow but dropping hard in the afternoon.  Some showers are possible through early afternoon.  I will update tomorrow morning on the wind potential as some areas will likely see wind advisories posted.

-Zack Green

Rain Ending As Snow For The Blackstone Valley Tuesday

Tomorrow is Tuesday and surprise, surprise...precipitation is in the forecast.  WBZ went back and found that there has been measurable preci...